build: use rollup to build vendor/autoprefixer.js

.gitignore

@@ -4,4 +4,6 @@
 pkg/
 
 .bundle
-*.lock
+Gemfile.lock
+
+build/node_modules/

build/autoprefixer.js

@@ -0,0 +1,22 @@
+import postcss from 'postcss'
+import autoprefixer from 'autoprefixer'
+
+export default {
+  process: (css, processOptions, pluginOptions) => {
+    // execjs does not support passing callback from ruby,
+    // which makes waiting for the promise to settle from async function impossible
+    var result = postcss([autoprefixer(pluginOptions)]).process(css, processOptions)
+
+    var warns  = result.warnings().map(function (i) {
+      delete i.plugin
+      return i.toString()
+    })
+
+    var map = result.map ? result.map.toString() : null
+    return  { css: result.css, map: map, warnings: warns }
+  },
+
+  info: (options) => {
+    return autoprefixer(options).info()
+  }
+}

build/package.json

@@ -0,0 +1,29 @@
+{
+  "name": "build",
+  "version": "1.0.0",
+  "main": "index.js",
+  "license": "MIT",
+  "browser": true,
+  "dependencies": {
+    "autoprefixer": "postcss/autoprefixer",
+    "nop": "^1.0.0",
+    "postcss": "postcss/postcss#ose",
+    "synchronous-promise": "^2.0.13",
+    "yarn": "^1.22.5"
+  },
+  "devDependencies": {
+    "@rollup/plugin-alias": "^3.1.1",
+    "@rollup/plugin-commonjs": "^15.0.0",
+    "@rollup/plugin-json": "^4.1.0",
+    "@rollup/plugin-node-resolve": "^9.0.0",
+    "@rollup/plugin-replace": "^2.3.3",
+    "rollup": "^2.26.10",
+    "rollup-plugin-node-polyfills": "^0.2.1"
+  },
+  "resolutions": {
+    "autoprefixer/postcss": "postcss/postcss#ose"
+  },
+  "scripts": {
+    "build": "yarn run rollup -c rollup.config.js"
+  }
+}

build/rollup.config.js

@@ -0,0 +1,42 @@
+import path from 'path'
+import alias from '@rollup/plugin-alias'
+import nodeResolve from '@rollup/plugin-node-resolve'
+import commonjs from '@rollup/plugin-commonjs'
+import json from '@rollup/plugin-json'
+import nodePolyfills from 'rollup-plugin-node-polyfills'
+import replace from '@rollup/plugin-replace'
+
+export default {
+  input: 'autoprefixer.js',
+  output: {
+    file: '../vendor/autoprefixer.js',
+    format: 'iife',
+    name: 'autoprefixer',
+    sourcemap: 'inline'
+  },
+  plugins: [
+    // this line slips into browser build, patch for now
+    replace({
+      "terminalHighlight.registerInput(Input)": '',
+      include: "node_modules/postcss/lib/input.js",
+      delimiters: ['', '']
+    }),
+    json(),
+    alias({
+      entries: [
+        { find: '@babel/register', replacement: 'nop' },
+        { find: '@babel/core', replacement: 'nop' },
+        { find: 'url', replacement: path.resolve(__dirname, 'url.js') }
+      ]
+    }),
+    commonjs({
+      transformMixedEsModules: true
+    }),
+    nodeResolve({
+      browser: true,
+      preferBuiltins: false,
+      extensions: [".mjs", ".js", ".json", ".node", ".es6"]
+    }),
+    nodePolyfills()
+  ]
+}

build/url.js

@@ -0,0 +1,8 @@
+module.exports = Object.assign(
+  {},
+  require("rollup-plugin-node-polyfills/polyfills/url.js"),
+  {
+    pathToFileURL: (path)=> { return `file:///${encodeURIComponent(path)}` },
+    fileURLToPath: (fileURL)=> { return decodeURIComponent(fileURL.repalce(/^file:\/\/\//, '')) }
+  }
+)